The Radiation Therapy Oncology Group is a clinical cooperative formed to conduct investigative trials in Radiation Oncology. This group formulates protocols which after appropriate pilot studies and group consideration are used by members of the entire group. The central organization serves to disseminate information and protocols and for data storage retrieval and analysis. The individual participating member institutions, of which we are one, further the work of the group by providing an environment in which the clinical trials can be carried out. Patients are entered into the various protocols and data about their treatment and subsequent course accumulated and pooled. The members of the working group at this institution are responsible for the actual clinical care and data accumulation for all patients entered from this institution. They participate as well in the organizational activities of the R.T.O.G. and in the development of protocols for use by the entire group. The objective of this activity is to allow an efficient and economical means for conducting clinical trials with the rapid integration of new biological concepts into clinical investigative programs and to thereby reduce the time between observations of a biological phenomena and its application to clinical care with ultimately improved cancer therapy.